64GB SDXC cards to arrive early next year

Toshiba's announced a new card based on the SDXC spec, which will eventually …

The continuing capacity ramping of Secure Digital cards will continue
basically uninterrupted through the next few years, as the flash card
vendors introduce yet another extension to the SD specification, called Secure Digital Extended Capacity. This week, Toshiba announced
the first card to launch on the new specification, a 64GB module
expected to ship next spring. Prices have not been announced, but the
new card capacities typically ship at prices slightly higher per unit
capacity than existing cards, so it's reasonable to speculate that a
cost of about $100-$150 is likely. Panasonic and PreTec had previously
SDXC announced cards with unknown launch dates.

The original SD spec was limited to 4GB card sizes (and 2GB and 4GB cards had compatibility problems with older readers), so in 2006 an extension was introduced, boosting maximum capacity to 32GB with a switch from FAT16 to the FAT32 file system and certain other minor tweaks. The SDHC spec could be sized up to 2TB without causing address size issues, but is limited by the spec to 32GB, a capacity first achieved last year.

Reading the new cards will require SDXC-compatible readers, which are likely to be available cheaply in USB interfaces and ship in lots of laptops at about the time cards appear. While this card boasts read speeds of 60MBps and write speeds of 35MBps, SDXC cards will eventually support read speeds as high as 300MB/s, we're told, which is within the bandwidth capability of USB 3.0. Capacities will range up to 2TB, so the spec may last up to ten years before another replacement is needed.�

A 2TB card would take about two hours to empty or fill at 300MBps, so it's possible that further enhancements in read speeds are due.

The new spec also brings a new file system to SD, exFAT, an extension of the FAT32 system with longer addresses, support for larger files and more granular logging, and other novel features. ExFAT, like FAT16 and FAT32, is owned by Microsoft and is more suited for memory cards than heavier-overhead file systems like HFS+ and NTFS. At present, exFAT is supported by Windows CE, Windows Vista, Windows 7. A patch is available to enable exFAT support on Windows XP, and an exFAT-supporting Linux kernel is under development. It's unknown when, if ever, OS X will support exFAT, but presumably it will happen eventually. If not, mac users would be unable to use SDXC cards.

Hopefully we'll see Apple licence the required technology. At the end of the day, Microsoft created exFAT, which is considerably different than the vanilla FAT. I don't think it is unwarranted them asking for a small amount in return.

So why was SDHC artificially limited to 32GB? I have plenty of devices that could benefit from the increased space of SDXC, and it sucks to have to change devices just to support yet another standard. Hopefully a firmware update can allow older devices to read SDXC cards (like for some SD -> SDHC readers), but good luck getting manufacturers of older devices to develop firmware updates.

FAT32 has subtle issues when you get above 32GB. This is why Microsoft has constrained the creation of greater than 32GB FAT32 partitions. It became apparent years later that there was a need for a lightweight file system for portable drives, thus exFAT.

It's pretty unlikely Mac users will be left without access once the market becomes real. Microsoft has more to gain from this being widely adopted than from treating it as a direct revenue source. I'd be surprised if Apple doesn't have their exFAT support on internal roadmaps already.

It is a disgrace that we are pushed into standardizing onto a new patent-laden but very mediocre filing system for the time to come. Especially when it is absolutely unnecessary.

Flash cards used FAT because it is supported by all Windows without further drivers, while being easy to implement with small embedded processors. Now that drivers are necessary, ANY filing system could do, so we could go for one that was patent free and technologically competent.

Why not use Apple's own HFS+ filing system? It is BSD licensed, high performance, well proven and already supported on Apple hardware as well as in Linux (which means on a huge legion of embedded computers). Windows would need an extra driver, but this is also true of exFAT, and Apple has the vehicle in iTunes to push that driver into many Windows installations, also gaining the possibility of using only HFS+ in iPods and iPhones.

Apple should push for HFS+ use in flashcards; they could very well succeed. Still, they don't seem interested, maybe because deeply inside (or not that deeply) they dislike flash cards as they dislike any vehicle that can transfer media in and out of Apple devices bypassing their control.

Linux own EXT filing systems would do, too, although it might be GPL licensed, which might make it unsuitable in some proprietary applications. Still, I believe it is BSD too, which would do just fine. There are drivers available for OSX and Windows, although some improvement would do them good. And it lacks Apple's iTunes to ram EXT into Windows.

There are very many other alternatives, only they are less well tried and supported. What they all have in common with HFS+ and EXT3/4 is being vastly better than exFAT as well as free.

Why are many excellent choices being ignored, while going straight for what is clearly the worst? Electronics device makers could gain performance and save money and trouble compared to licensing FAT and exFAT from Microsoft.

But somehow, this is not to be. Sadly, I firmly believe that it will all work out the worst way. exFAT will rule, patent threats will be thrown, suits will fly, a new Microsoft tax will be tagged onto many electronic devices, and Linux devices (not only computers, but TVs, video cameras, media players etc.) will have problems to use standard media.

Could someone who both knows FS stuff and know how to explain things simply please explain why FAT, in its various flavors, remains a better solution for these types of devices than what I am going to call completely ignorantly more "sophisticated" file systems? The article mentions HFS+ and NTFS and describes them as "heavier overhead." What does that mean and why is that important for devices like this?

Originally posted by Lobotomik:Flash cards used FAT because it is supported by all Windows without further drivers, while being easy to implement with small embedded processors. Now that drivers are necessary...

Er, RTFA.Drivers are NOT necessary for either the current (Windows 7) or previous (Windows Vista) versions of Windows.

quote:

Originally posted by Lobotomik:There are very many other alternatives, only they are less well tried and supported. What they all have in common with HFS+ and EXT3/4 is being vastly better than exFAT as well as free.

"better" at what ? They're all ludicrously complex compared to exFAT - it's a very simple filesystem, designed specifically for the purpose. I have no idea where all your hate is coming from !

Lobotomik does have a point. While I dont have any idea of the performance differences, why should the industry be forced to use exFAT? If Microsoft wants to open source exFAT, fine. But there are many free filesystems that could be chosen that would be better for everyone (except Microsoft). We all know that the reason why exFAT was chosen was because the chip makers need Microsoft support.

Would this be like SDHC where a firmware update could enable current readers to use SDXC? My laptop shipped with a vanilla SD card reader, but system updates in XP and the use of Ubuntu mean it can fully read/write a 16GB SDHC card.

Originally posted by laudunum:Could someone who both knows FS stuff and know how to explain things simply please explain why FAT, in its various flavors, remains a better solution for these types of devices than what I am going to call completely ignorantly more "sophisticated" file systems? The article mentions HFS+ and NTFS and describes them as "heavier overhead." What does that mean and why is that important for devices like this?

Journalled Filesystems such as NTFS inherently commit more writes to the media. This kinda sucks for media like flash that is relatively write-limited. Removable flash cards are also intended to be relatively cheap and don't have the same write lifetimes or wear leveling capabilities that higher-end flash used in SSDs does.

Originally posted by Lobotomik:It is a disgrace that we are pushed into standardizing onto a new patent-laden but very mediocre filing system for the time to come. Especially when it is absolutely unnecessary.

Flash cards used FAT because it is supported by all Windows without further drivers, while being easy to implement with small embedded processors. Now that drivers are necessary, ANY filing system could do, so we could go for one that was patent free and technologically competent.

First off I agree with you the situation sucks, that said...

Have you ever written firmware for an embedded device that accesses a flash drive?

I have (a few times now), and trust me, given the choice between FAT and pretty much anything else I'd choose FAT.

Remember, the devices that us SD cards are many times NOT running a full OS (or pretty much anything coming even close to an OS). They are small devices with only a few K of firmware (think digital cameras, photo frames, MP3 players, etc).

The code to read a FAT volume is very simple, I've done it (using many shortcuts) in about 1k of code (PIC microcontroller). The amount of code (and MUCH more importantly memory) to read a NTFS/HFS+/EXT volume is MUCH MUCH MUCH more.

FAT32, assuming similar shortcuts is also very light on the code front (a little heavier on memory, but not much).

exFAT is a little more complicated then FAT32, but on the whole is still a VERY simple filesystem, and writing firmware to read from it (I haven't done it yet) looks pretty easy if you're familiar with FAT/FAT32 (an odd trivial bit is FAT12 is harder to write for then FAT16!).

Again, I wish there were something more free then FAT, but the fact remains is it's pretty much the simplest file system out there, and when you're talking about devices that have to last days or weeks on a battery and fit in your pocket, MB of driver code is about as ridiculous as using a row boat to cross the Atlantic.

y not design XC spec to read@SATA II or SATA III rates so that when USB 4 or 5 comes along, it'll simply "catch up" to SSD-like rates? conceptually, these 'solid state' memory is basically SSD's miniaturized. i don't get the capping of the read rate@300MBps, y not multi GBps already. well hell even that's freakin' slow. should be multi-petabytes or exabytes per second.

Finally, thanks Ars, I have been barking load and hard about SDXC using exFAT only. Hoping someone news site would pick up the god damn insane stupid issue.

So does everyone require to pay M$ to liscense exFAT since it is not a Open Standard. ( I dont care if it is even open source, Open Standard was at least the requirement)

I dont know if their are payment for licensing, royalties for SD Card, i suspect their are at least for their Logo. But i seriously hope those include exFAT license inside.

Apple has already mention in their support notes that their card reader built in MBP far exceed the current SDHC spec, and should be able to read SDXC card with those speed requirement. The only problem left is software.

Originally posted by iwod:My problem is, What happen if M$ decided i dont like you, and not grant you a license to include exFAT?

Then you'd be screwed

In all seriousness though, I suspect they'll licence it out to absolutely anyone who asks. It wouldn't be much good as a flash-memory-filesystem if the licensing was restricted to certain parties only !